A group of people who claim they were tricked into forming relationships with undercover police officers can go ahead with their High Court damages claims.

Police used undercover officers to infiltrate some groups of environmental activists [PA]

Mr Justice Tugendhat ruled that it would not be an abuse of process at this stage to pursue the cases brought under common law by 10 women and one man, who want compensation for emotional trauma allegedly caused by officers infiltrating environmental activist groups.

But he said that claims brought under the Human Rights Act against the Metropolitan Police and South Wales Police should be determined by the Investigatory Powers Tribunal (IPT).

Formed in 2000, it holds a number of hearings in private and has no obligation to take oral evidence.

He stayed the High Court proceedings pending the determination of proceedings at the IPT, saying it was temporary and should not be long if the IPT claims were pursued expeditiously.

The women say they had a sexual relationship with a man who was later discovered to be a covert human intelligence source (CHIS), while the male claimant alleges a non-sexual relationship.

The police had argued that the IPT was the appropriate forum for all the claims as Parliament intended such cases to be decided by a specialist tribunal with a specially tailored procedure.

Some of the claimants say they had relationships with Mark Kennedy, the undercover police officer who spent seven years spying on environmental activists posing as long-haired dropout climber Mark "Flash" Stone.

Legal firm Birnberg Peirce said later that the ruling on the Human Rights Act aspect only affected five women and the man - who were in relationships after the legislation came into force in Britain in 2000.

Solicitor Harriet Wistrich said: "This decision prevents both the claimants and the public from seeing the extent of the violations of human rights and abuses of public office perpetrated by these undercover units. The claimants have already suffered a gross violation of their privacy and abuse of trust by the police. If the case is dealt with by the IPT, they will be denied access to justice and may never discover why they were thus violated by the state."